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| 1 // Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file |
| 2 // for details. All rights reserved. Use of this source code is governed by a |
| 3 // BSD-style license that can be found in the LICENSE file. |
| 4 |
| 5 part of custom_element; |
| 6 |
| 7 /** |
| 8 * Represents an attribute map of model values. If any items are added, |
| 9 * removed, or replaced, then observers that are listening to [changes] |
| 10 * will be notified. |
| 11 */ |
| 12 class _AttributeMap implements Map<String, String> { |
| 13 final CustomElement _element; |
| 14 final Map<String, String> _map; |
| 15 |
| 16 /** Creates an attribute map wrapping the host attributes. */ |
| 17 _AttributeMap(CustomElement element) |
| 18 : _element = element, _map = element.host.attributes; |
| 19 |
| 20 // Forward all read methods: |
| 21 Iterable<String> get keys => _map.keys; |
| 22 Iterable<String> get values => _map.values; |
| 23 int get length =>_map.length; |
| 24 bool get isEmpty => _map.isEmpty; |
| 25 bool get isNotEmpty => _map.isNotEmpty; |
| 26 bool containsValue(Object value) => _map.containsValue(value); |
| 27 bool containsKey(Object key) => _map.containsKey(key); |
| 28 String operator [](Object key) => _map[key]; |
| 29 void forEach(void f(String key, String value)) => _map.forEach(f); |
| 30 String toString() => _map.toString(); |
| 31 |
| 32 // Override the write methods and ensure attributeChanged is called: |
| 33 void operator []=(String key, String value) { |
| 34 int len = _map.length; |
| 35 String oldValue = _map[key]; |
| 36 _map[key] = value; |
| 37 if (len != _map.length || !identical(oldValue, value)) { |
| 38 _element.attributeChanged(key, oldValue); |
| 39 } |
| 40 } |
| 41 |
| 42 void addAll(Map<String, String> other) { |
| 43 other.forEach((String key, String value) { this[key] = value; }); |
| 44 } |
| 45 |
| 46 String putIfAbsent(String key, String ifAbsent()) { |
| 47 int len = _map.length; |
| 48 String result = _map.putIfAbsent(key, ifAbsent); |
| 49 if (len != _map.length) { |
| 50 _element.attributeChanged(key, null); |
| 51 } |
| 52 return result; |
| 53 } |
| 54 |
| 55 String remove(Object key) { |
| 56 int len = _map.length; |
| 57 String result = _map.remove(key); |
| 58 if (len != _map.length) { |
| 59 _element.attributeChanged(key, result); |
| 60 } |
| 61 return result; |
| 62 } |
| 63 |
| 64 void clear() { |
| 65 int len = _map.length; |
| 66 if (len > 0) { |
| 67 _map.forEach((key, value) { |
| 68 _element.attributeChanged(key, value); |
| 69 }); |
| 70 } |
| 71 _map.clear(); |
| 72 } |
| 73 |
| 74 /** |
| 75 * This is not a [Map] method. We use it to implement "set attributes", which |
| 76 * is a global replace operation. Rather than [clear] followed by [addAll], |
| 77 * we try to be a bit smarter. |
| 78 */ |
| 79 void _replaceAll(Map<String, String> other) { |
| 80 for (var key in keys) { |
| 81 if (!other.containsKey(key)) remove(key); |
| 82 } |
| 83 addAll(other); |
| 84 } |
| 85 } |
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